SoftWind project
Thrust force
Dynamical loads
Rotor control/ command testing
Upscaling capability (Protor> 5MW)
Froude-scaled « thrust » with drag disk + + - - - - -
Froude-scaled thrust geometry (Froude scaling) + - - -
Rotor performance scaled (Low Reynolds number airfoils) ++ -+ - -
SIL ++ +/++ ++ ++
Aerodynamic Thrust Modelling for Wave Tank Tests of FOWT
SoftWind is a 3-year project that aims at developing an experimental setup dedicated to the model testing of floating wind turbines in a wave tank. The experimental modelling methodology is based on an Software-In-the-Loop (SIL) approach that combines numerical modelling with experimental modelling.
• The rotor is represented by an actuator placed at the top of the tower. The actuator is in charge of emulating the response of the rotor.
• The aerodynamic forces are simulated numerically and are communicated to the actuator. The actuator applies the forces to the model.
• The motion of the model is affected by the actuator forces.
• In response sensors placed on the model inform the numerical model on the nacelle position and speed.
Basic Principle of SIL Methodology for Wave Tank Tests of FOWT
SIL approach Drag disk Strictly Froude-scaled model
SOFTWIND Current Experimental Setup
- Performance Assessment
𝐻𝑠 [m] 𝑇𝑝 [s] 𝑈𝑤 [m/s] Mean thrust [kN]
LC1 3 5 11.4 680
LC2 4 5 18 320
LC3 6 10 11.4 680
LC4 7 10 18 320
LC5 7 17 11.4 680
LC6 8 17 18 320
Load Case LC1 LC2 LC3 LC4 LC5 LC6
Mean Thrust (N) 25 12.5 25 12 24 12
Error (%) 3 5 5 10 4 5
• List of wind and waves load cases
• Relative error on the thrust force for the 6 load cases
Test with imposed motions and 1 DOF emulator
1st Wave tank test with 1 DOF emulator
2nd experimental test with imposed motions and advanced emulator
2nd Wave tank tests with advanced emulator
October 2020: End of the project
October 2017: Kick-Off
Key milestones of the project
In parallel, there are ongoing works focusing on the design of an advanced emulator composed by multiple actuators (fans).
Low Re number airfoils
Actuators used in SIL Approaches dedicated to FOWT
CENER
• 1 ducted fan on-board
SINTEF
• 6 force-controlled wires with winch units
MARIN
• 6 force-controlled wires with winch units
IH Cantabria
• 6 on-board fans on a frame
Umaine
• 2 force-controlled wires with winch units
UC Berkeley
• 2 fans on rotating masts
Accelometer Balance
COMPACT RIO Generator CompactRIO controller
Qualysis motion capture system
A test bench with a single actuator is currently tested. The purpose of this set up is the validation of :
• the communication protocols, • the real-time execution of the
numerical model, • the motion and force observers, • the preliminary actuator model
identification.
Preliminary validation tests consist in imposed motions by means of a hexapod and will be followed by wave tank tests next September.
6 DoF “Symétrie” Hexapod
A ducted fan Schübeler DS-94-DIA HST
Control room